For example, when a glass substrate (including a brittle material) is cut into a desired size, a cutting edge of a cutter wheel is pressed onto a surface of the brittle material with a predetermined force and is moved on the surface of the glass substrate. As a result, a scribing line is formed (hereinafter, referred to as a “scribing step”). Thereafter, a predetermined force is applied to the glass substrate along the scribing line (hereinafter, referred to as a “breaking step”). As a result, the glass substrate is cut along the scribing line.
FIG. 7 shows an example of a structure of a conventional scribing apparatus 10. The scribing apparatus 10 performs the scribing step.
The scribing apparatus 10 includes a table 11, a first guide rail 12A, a second guide rail 12B and a ball screw 13.
The table 11 is structured so as to be rotatable in a horizontal plane. A vacuum adsorption means (not shown) is provided in the table 11. The vacuum adsorption means fixes a substrate G (e.g., brittle substrate including a glass plate) mounted on the table 11 to the table 11. The first guide rail 12A and the second guide rail 12B support the table 11 such that the table 11 is movable in the Y-direction. The first guide rail 12A and the second guide rail 12B are provided in parallel to each other. The ball screw 13 moves the table 11 along the first guide rail 12A and the second guide rail 12B.
The scribing apparatus 10 further includes a first pillar 19A, a second pillar 19B, a guide bar 14, a sliding unit 15 and a first motor 16.
The first pillar 19A and the second pillar 19B are vertically provided on a base of the scribing apparatus 10 having the first guide rail 12A and the second guide rail 12B interposed therebetween. The guide bar 14 is provided above the table 11 along the X-direction and constructed between the first pillar 19A and the second pillar 19B. The sliding unit 15 is provided on the guide bar 14 so as to be slidable. The first motor 16 slides the sliding unit 15.
The scribing apparatus 10 further includes a scribing head 9, a second motor 17 for moving the scribing head 9 upward and downward, a first CCD camera 18A and a second CCD camera 18B. The second motor 17 holds the scribing head 9 at a predetermined height in the scribing step. The first CCD camera 18A and the second CCD camera 18B are provided above the guide bar 14 and detect an alignment mark formed on the substrate G.
The scribing head 9 is provided in the sliding unit 15. The scribing head 9 includes a cutter wheel 29.
The scribing head 9 presses the cutter wheel 29 onto the surface of the substrate G. When the motor 16 slides the sliding unit 15, the scribing head 9 moves along the guide bar 14. As a result, the cutter wheel 29 moves on the surface of the substrate G while it is being pressed onto the surface of the substrate G, and a scribing line is formed on the surface of the substrate G.
International Publication No. WO03/011777 pamphlet (Reference 1) discloses a scribing head. This scribing head includes a servo motor and a cutter wheel 29. The scribing head is structured such that the torque of a rotation axis of the servo motor is transmitted to the cutter wheel 29 directly or via a gear, and the cutter wheel 29 is pressed onto the surface of the substrate G. Since the cutter wheel 29 is pressed onto the substrate G with a predetermined force by the servo motor, for example, when compared to the case in which the cutter wheel 29 is pressed onto the substrate G with a predetermined force by an air cylinder, an excellent temporal followablity with respect to the change of reaction force from the substrate G, and an excellent controllability and responsiveness with respect to the magnitude of the reaction force are obtained.
FIG. 8 shows an example of a structure of a conventional scribing head 9. The scribing head 9 is a scribing head disclosed in Reference 1. The scribing head 9 is structured so as to directly transmit the torque of the rotation axis of the servo motor to the cutter wheel 29.
The scribing head 9 includes a servo motor 402, a holder holding member 404, a cutting edge holder 28 which is held by the holder holding member 404 and a cutter wheel 29 which is rotatable about a pin inserted at the lower end of the cutting edge holder 28.
The servo motor 402 of scribing head 9 is, for example, held by a sliding unit 15 (see FIG. 7). When a rotation axis 402A of the servo motor 402 is turned, the cutter wheel 29 is moved upward and downward via the holder holding member 404 and the cutting edge holder 28. Owing to such a structure, the servo motor 402 generates a torque in a direction in which the rotation axis 402A turns clockwise (see FIG. 8), and presses the cutter wheel 29 onto a brittle material substrate.
FIG. 9 shows a structure of another example of the conventional scribing head 400. FIG. 9(a) shows a side view of the scribing head 400. FIG. 9(b) shows a front view of relevant parts of the scribing head 400. The scribing head 400 is a scribing head disclosed in Reference 1. In FIG. 9, the same components as those shown in FIG. 8 are denoted by the same reference numerals, and the description thereof will be omitted.
The scribing head 400 includes a first side wall 401A, a second side wall 401B, a servo motor 402 which is fixed between the first side wall 401A and the second side wall 401B in an upside down manner, an L-shaped holder holding member 404, a spindle 403, which is provided at the bottom portion of the first side wall 401A and the second side wall 401B, for supporting the holder holding member 404 such that the holder holding member 404 is rotatable, and a scribing line forming mechanism 21. The scribing line forming mechanism 21 includes a turning axis 27, a cutting edge holder 28 and a cutter wheel 29. The cutting edge holder 28 is fixed to the turning axis 27 and is held by the holder holding member 404 so as to be turnable via the turning axis 27.
A first bevel gear 405A is firmly fixed to an output axis of the servo motor 402. A second bevel gear 405B is firmly fixed to the spindle 403. The first bevel gear 405A and the second bevel gear 405B are provided so as to engage with each other. Thus, when the servo motor 402 is rotated in a positive direction or a negative direction, the holder holding member 404 turns about the spindle 403, and the scribing line forming mechanism 21 moves upward or downward, respectively. Owing to such a structure, the servo motor 402 generates a torque in a direction in which the spindle 403 turns clockwise (see FIG. 9(b)) and presses the cutter wheel 29 onto the brittle material substrate.
Furthermore, Japanese Laid-Open Publication No. 2001-206727 (Reference 2) discloses a scribing head A which is another example of the conventional scribing head. The scribing head A, similar to the scribing head 400, transmits the motive power of a servo motor to a cutter wheel via a gear (specifically, a rack-and-pinion).
Reference 1: International Publication No. WO03/011777 pamphlet
Reference 2: Japanese Laid-Open Publication No. 2001-206727